Tin-doped indium oxide microparticle dispersion, process for producing the same, interlayer for laminated glass having heat-ray blocking property produced with the dispersion and laminated glass

ABSTRACT

A dispersion of tin-doped indium oxide fine particles has tin-doped indium oxide fine particles, a plasticizer for an interlayer film, an organic solvent containing alcohols as a main component, and a dispersion stabilizer, wherein under measuring conditions of a concentration of tin-doped indium oxide fine particles of 0.7% by weight and an optical path length of a glass cell of 1 mm, a visible light transmittance is 80% or more, a solar radiation transmittance at a wavelength within a range from 300 nm to 2100 nm is ¾ or less of the visible light transmittance, a haze value is 1.0% or less, and a reflection yellow index is −20 or more.

TECHNICAL FIELD

The present invention relates to a dispersion of tin-doped indium oxidefine particles, which can be used in the manufacture of an interlayerfilm for laminated glass, to a method for manufacturing the dispersion,to an interlayer film for laminated glass with heat ray shieldproperties, and a laminated glass therewith.

This application claims priority on Japanese Patent Application No.2003-427446 filed on Dec. 24, 2003, the contents of which areincorporated herein by reference.

BACKGROUND ART

In general, a laminated glass has a structure obtained by interposing aninterlayer film for laminated glass (hereinafter also referred to simplyas an interlayer film) including a polyvinyl acetal resin such aspolyvinyl butyral resin plasticized by a plasticizer between at least apair of glass sheets, and integrating them. The laminated glass havingsuch a structure is excellent in safety because fragments of glasshardly scatter when broken by an exterior impact, and therefore it iswidely used as a window glass for vehicles such as automobiles andaircrafts, and for buildings.

However, such a laminated glass including an interlayer film wasexcellent in safety, but was inferior in heat shield properties. Ingeneral, infrared radiation having a wavelength of 780 nm or more, whichis longer than that of visible light, is referred to as heat raybecause, inspite of its small energy amount such as about 10% ascompared with ultraviolet radiation, it has a large thermal action andis released as heat to cause temperature rise when absorbed by asubstance. A laminated glass capable of effectively shielding this heatray has been required. When it becomes possible to shield infraredradiations having a large thermal action among light rays incident uponautomotive front and side glasses, heat shield properties are enhancedand thus temperature rise in the automobile can be suppressed. Since thearea of the automotive glass portion tends to increase, recently, it hasbecome necessary to enhance heat shield properties of the laminatedglass, thereby imparting a heat ray shield function to the glass openingportion.

As the laminated glass having enhanced heat shield properties, forexample, there has been known a laminated glass including an interlayerfilm having a transparent resin mixed with a plasticizer containingtin-doped indium oxide fine particles (hereinafter also referred to asITO fine particles) to a transparent resin (see Patent Document 1:Japanese Patent No. 3,040,681). This publication discloses, as theinterlayer film for laminated glass, an interlayer film obtained bymixing ITO fine particles having a particle size limited to 0.1 μm orless so as not to impair transparency, an anionic surfactant andphthalic acid di-2-ethylhexyl as a plasticizer to prepare a dispersionof ITO fine particles containing ITO fine particles dispersed therein,kneading the dispersion with a polyvinyl butyral resin, and forming thekneaded mixture into a film.

As an interlayer film composition for laminated glass having heat shieldproperties, there has been known a composition obtained by mixing adispersion containing ITO fine particles, a higher fatty acid ester, anda plasticizer with a resin (see Patent Document 2: Japanese PatentApplication, First Publication No. 2001-233643). In the case of thisinterlayer film composition, the higher fatty acid ester such aspolyglycerin fatty acid ester is added so as to enhance dispersibilityof ITO fine particles.

However, a conventional interlayer film for laminated glass composition,or a dispersion of ITO fine particles used for the interlayer filmcomposition may be inferior in transparency because clouding occurs at acertain angle, inspite of the same haze value as an indicator oftransparency. Also, there is a problem in that, when using aconventional dispersant in the case of dispersing ITO fine particles inthe plasticizer, it becomes difficult to control the degree of adhesionat the interface between the glass and the interlayer film of thelaminated glass. Also, there is a problem in that it becomes difficultto control a variation in the degree of adhesion between the glass andthe interlayer film due to a change in moisture of the interlayer film.Furthermore, there is a problem in that, when the dispersion of ITO fineparticles is diluted with a plasticizer for an interlayer film, ITO fineparticles are converted into agglomerated particles due to poordispersion, that is, so-called solvent shock phenomenon arises and thustransparency is lowered.

There have been known a composition obtained by adding triethyleneglycol di-2-hexanoate (3GO) as a plasticizer to a solution containingITO fine particles dispersed in polyphosphate ester and acetylacetone(see Patent Document 3: Japanese Patent Application, First PublicationNo. 2002-293583) and a composition obtained by further mixing thecomposition with 2-ethylhexanoic acid (see Patent Document 4: JapanesePatent Application, First Publication No. 2001-302289). However, all ofthese compositions have a drawback in that they are free of alcohols andhave high hydrophobicity, and thus ITO fine particles are inferior inaffinity with the solution and solvent shock may arise. Also, there is adrawback in that dispersion proprety drastically vary depending on thekind of the plasticizer for the interlayer film.

The present invention has been made so as to solve the above problems ofthe prior art with respect to a dispersion of ITO fine particles havingheat ray shield properties, and an interlayer film including thedispersion. The present invention provides a dispersion of ITO fineparticles having excellent transparency and heat shield properties byadjusting the haze value to a fixed value or less, and controlling areflection value measured by a goniophotometric measurement as anindicator and a reflection yellow index (YI) having a correlation withthe measured reflection value as an indicator within a fixed range, andalso provides an interlayer film including the dispersion of ITO fineparticles, and a heat ray shield laminated glass including theinterlayer film.

Furthermore, the present invention provides a dispersion of ITO fineparticles which easily adjusts the degree of adhesion due to acombination of dispersion stabilizers, which is excellent indispersibility of ITO fine particles, which easily suppresses avariation in the degree of adhesion at the interface between the glassand the interlayer film due to a change in moisture of the interlayerfilm, and which is also less likely to cause solvent shock, and alsoprovides an interlayer film including the dispersion of ITO fineparticles, and a heat ray shield laminated glass including theinterlayer film.

DISCLOSURE OF THE INVENTION

The present invention relates to the following dispersion of tin-dopedindium oxide fine particles, and to a method for manufacturing the same.

(1) A dispersion of tin-doped indium oxide fine particles, thedispersion includes tin-doped indium oxide fine particles, a plasticizerfor an interlayer film, an organic solvent containing alcohols as a maincomponent, and a dispersion stabilizer, wherein under measuringconditions of the concentration of tin-doped indium oxide fine particlesof 0.7% by weight and an optical path length of a glass cell of 1 mm, avisible light transmittance is 80% or more, a solar radiationtransmittance at a wavelength within a range from 300 nm to 2100 nm is ¾or less of the visible light transmittance, a haze value is 1.0% orless, and a reflection yellow index is −20 or more.

In this case, there can be obtained a dispersion of tin-doped indiumoxide fine particles which is excellent in dispersibility of tin-dopedindium oxide fine particles and has high transparency at a certainangle, and which is also less likely to cause solvent shock andmaintains good dispersion state of tin-doped indium oxide fine particleswhen the dispersion is mixed with the resin. This dispersion oftin-doped indium oxide fine particles is suited for the manufacture ofan interlayer film for laminated glass, and an interlayer film forlaminated glass with excellent heat ray shield properties and alaminated glass including the same can be obtained by using thedispersion.

(2) The dispersion of tin-doped indium oxide fine particles according to(1), wherein instead of the reflection yellow index being −20 or more,or with the reflection yellow index being −20 or more, under measuringconditions of an optical path length of a glass cell of 1 mm, areflection value measured at 0 degrees among reflected lightdistribution at an incidence angle of 45 degrees measured by agoniophotometric measurement is 30 or less.

(3) The dispersion of tin-doped indium oxide fine particles according to(1), wherein the plasticizer for an interlayer film is at least oneselected from the group consisting of dihexyl adipate, triethyleneglycol di-2-ethylhexanoate, tetraethylene glycol di-2-ethylhexanoate,triethylene glycol di-2-ethyl butyrate, tetraethylene glycol di-2-ethylbutyrate, tetraethylene glycol di-heptanoate, and triethylene glycoldi-heptanoate.

(4) The dispersion of tin-doped indium oxide fine particles according to(1), wherein the alcohols include at least one selected from the groupconsisting of methanol, ethanol, propanol, isopropanol, n-butanol,isobutanol, sec-butanol, tert-butanol, lauryl alcohol, diacetonealcohol, cyclohexanol, ethylene glycol, diethylene glycol andtriethylene glycol.

(5) The dispersion of tin-doped indium oxide fine particles according to(1), wherein the dispersion stabilizer is a compound having at least oneatom selected from the group consisting of nitrogen, phosphorus, andchalcogen atoms.

(6) The dispersion of tin-doped indium oxide fine particles according to(5), wherein the dispersion stabilizer is at least one selected from thegroup consisting of sulfate ester-based compound, phosphate ester-basedcompound, ricinoleic acid, polyricinoleic acid, polycarboxylic acid,polyhydric alcohol type surfactant, polyvinyl alcohol, and polyvinylbutyral.

(7) The dispersion of tin-doped indium oxide fine particles according to(1), wherein the dispersion stabilizer is at least one selected from thegroup consisting of chelate, inorganic acid and organic acid.

(8) The dispersion of tin-doped indium oxide fine particles according to(1), wherein the dispersion of tin-doped indium oxide fine particlescontains, as the dispersion stabilizer, three components of phosphateester-based compound, organic acid, and chelate.

(9) The dispersion of tin-doped indium oxide fine particles according to(1), wherein a concentration of the ITO fine particles is from 0.1 to95% by weight, a content of the plasticizer for an interlayer film isfrom 1 to 99.9% by weight, a content of the organic solvent containingalcohols as a main component is from 0.02 to 25% by weight, and acontent of the dispersion stabilizer is from 0.0025 to 30% by weight.

(10) The dispersion of tin-doped indium oxide fine particles accordingto (1), wherein the dispersion of tin-doped indium oxide fine particlesis obtained by diluting a dispersion of tin-doped indium oxide fineparticles which contains tin-doped indium oxide fine particles, aplasticizer for an interlayer film, an organic solvent containingalcohols as a main component, and a dispersion stabilizer, and in whicha concentration of the tin-doped indium oxide fine particles is from 0.1to 95% by weight, with a plasticizer for an interlayer film, or aplasticizer for an interlayer film containing an organic solventcontaining alcohols as a main component and/or a dispersion stabilizer.

(11) The dispersion of tin-doped indium oxide fine particles accordingto (1), wherein, when a concentration of the tin-doped indium oxide fineparticles is adjusted to 10.0% by weight by diluting a dispersion oftin-doped indium oxide fine particles having the concentration of thetin-doped indium oxide fine particles of 10.0% by weight or more, orwhen a concentration of the tin-doped indium oxide fine particles isadjusted to 40.0% by weight by diluting a dispersion of tin-doped indiumoxide fine particles having the concentration of the tin-doped indiumoxide fine particles of 40.0% by weight or more, a mean volume particlesize of the tin-doped indium oxide fine particles is 80 nm or less, anda particle size at 90% accumulation (D90) is 160 nm or less.

(12) The dispersion of tin-doped indium oxide fine particles accordingto (1), wherein a primary average particle size of the tin-doped indiumoxide fine particles is 0.2 μm or less.

(13) The dispersion of tin-doped indium oxide fine particles accordingto (1), wherein a lattice constant of a tin-doped indium oxide fineparticle crystal is from 10.11 to 10.16 Å.

(14) A method for manufacturing the dispersion of tin-doped indium oxidefine particles of any one of (1) to (13), includes mixing an organicsolvent containing alcohols as a main component, a dispersionstabilizer, tin-doped indium oxide fine particles and plasticizer for aninterlayer film, thereby dispersing the tin-doped indium oxide fineparticles.

(15) The method for manufacturing a dispersion of tin-doped indium oxidefine particles according to (14), wherein a mixed solution containingthe organic solvent containing the alcohols as a main component, thedispersion stabilizer, and the tin-doped indium oxide fine particles isprepared, and this mixed solution is mixed with the plasticizer for aninterlayer film to obtain a dispersion of tin-doped indium oxide fineparticles.

(16) The method for manufacturing a dispersion of tin-doped indium oxidefine-particles according to (15), wherein the mixed solution containingthe organic solvent containing the alcohols as a main component, thedispersion stabilizer, and the tin-doped indium oxide fine particles isprepared, and this mixed solution is added to the plasticizer for aninterlayer film, or the plasticizer for an interlayer film is added tothis mixed solution, thereby dispersing the tin-doped indium oxide fineparticles.

(17) The method for manufacturing a dispersion of tin-doped indium oxidefine particles according to (15), wherein a plasticizer containing anorganic solvent containing alcohols as a main component or a dispersionstabilizer is used as the plasticizer for an interlayer film.

Also, the present invention relates to the following interlayer film forlaminated glass with heat ray shield properties, and to a laminatedglass therewith

(18) An interlayer film for heat shield laminated glass, is formed byusing a resin composition of a mixture of the dispersion of tin-dopedindium oxide fine particles of any one of (1) to (13) and a resin,wherein, under the measuring conditions in which the interlayer filmhaving a thickness of 0.76 mm is interposed between clear glass sheetshaving a thickness of 2.5 mm, electromagnetic wave shield properties ata frequency of 0.1 MHz to 26.5 GHz is 10 dB or less, a haze value is1.0% or less, a visible light transmittance is 70% or more, a solarradiation transmittance at a wavelength within a range from 300 to 2100nm is 80% or less of the visible light transmittance, lo and areflection yellow index is −12 or more.

(19) The interlayer film for laminated glass according to (18), whereininstead of the reflection yellow index being −12 or more or with thereflection yellow index being −12 or more, a reflection value at 0degrees among reflected light distribution at an incidence angle of 45degrees measured by a goniophotometric measurement is 25 or less.

(20) The interlayer film for laminated glass according to (18), wherein20 to 60 parts by weight of the plasticizer for an interlayer film and0.1 to 3 parts by weight of the tin-doped indium oxide fine particlesbased on 100 parts by weight of a polyvinyl acetal resin are contained.

(21) The interlayer film for laminated glass according to (20), whereinthe polyvinyl acetal resin is a polyvinyl butyral resin,

(22) The interlayer film for laminated glass according to (18), whereinthe resin composition obtained by mixing the dispersion of tin-dopedindium oxide fine particles with the resin further contains an alkalimetal salt and/or an alkali earth metal salt as an adhesion adjustor.

(23) The interlayer film for laminated glass according to (18), whereinthe tin-doped indium oxide fine particles have an average particle sizeof 80 nm or less and are dispersed such that a number of particleshaving a particle size of 100 nm or more is one per μm² or less.

(24) A laminated glass includes the interlayer film for laminated glassof any one of (18) to (23)

(25) The laminated glass according to (24) wherein the laminated glasshas heat ray shield properties in which electromagnetic wave shieldperformance at a frequency of 0.1 MHz to 26.5 GHz is 10 dB or less, ahaze value is 1.0% or less, a visible light transmittance is 70% ormore, a solar radiation transmittance at a wavelength within a rangefrom 300 to 2100 nm is 80% or less of the visible light transmittance,and a reflection yellow index is −12 or more.

(26) The laminated glass according to (25), wherein instead thereflection yellow index being −12 or more, or with the reflection yellowindex being −12 or more, a reflection value at 0 degrees among reflectedlight distribution at an incidence angle of 45 degrees measured by agoniophotometric measurement is 25 or less.

The present invention will now be described in detail.

The dispersion of tin-doped indium oxide fine particles of the presentinvention is a dispersion of tin-doped indium oxide fine particles(hereinafter also referred to as a dispersion of ITO fine particles)including tin-doped indium oxide fine particles, a plasticizer for aninterlayer film, an organic solvent containing alcohols as a maincomponent (hereinafter also referred to as an alcohol solvent), and adispersion stabilizer, wherein under measuring conditions of theconcentration of tin-doped indium oxide fine particles is 0.7% by weightand an optical path length of a glass cell of 1 mm, a visible lighttransmittance is 80% or more, a solar radiation transmittance at awavelength within a range from 300 to 2100 nm is ¾ or less of thevisible light transmittance, a haze value is 1.0% or less, and areflection yellow index is −20 or more.

In the dispersion of ITO fine particles of the present invention,instead of the reflection yellow index being −20 or more, or with thereflection yellow index being −20 or more, a reflection value at 0degrees among reflected light distribution at an incidence angle of 45degrees measured by a goniophotometric measurement is 30 or less.

The ITO fine particles preferably have a primary average particle sizeof 0.2 μm or less. In the case in which the primary average particlesize is more than 0.2 μm, the haze value of the resulting interlayerfilm, in its turn, the haze value of the laminated glass becomes worse,or clouding may be caused by scattering of visible light due to ITO fineparticles. The primary average particle size is more preferably 0.1 μmor less, and still more preferably 0.08 μm or less. In the ITO fineparticles, a lattice constant of its crystal is preferably in a rangefrom 10.11 to 10.16 Å. In the case in which the lattice constant is notwithin the above range, sufficient heat ray shield effect may not beexerted.

The method for manufacturing the ITO fine particles is not specificallylimited. For example, there can be exemplified a method formanufacturing ITO fine particles, which includes reacting an aqueoussolution containing a water-soluble salt of indium chloride and a smallamount of tin chloride with an alkali, thereby coprecipitating ahydroxide of indium and tin, and annealing the coprecipitate as amaterial with heating in nitrogen free of oxygen to convert thecoprecipitate into an oxide.

In the dispersion of ITO fine particles of the present invention, theplasticizer for an interlayer film functions as a dispersion medium fordispersing the ITO fine particles. This plasticizer for an interlayerfilm is not specifically limited as long as it is conventionally usedfor a polyvinyl acetal resin, and a known plasticizer which is generallyused as a plasticizer for an interlayer film can be used. For example,there can be used organic ester-based plasticizers such as monobasicacid ester and polybasic acid ester; and phosphoric acid-basedplasticizers such as organic phosphoric acid-based and organicphosphorous acid-based plasticizers.

Among the above organic ester-based plasticizers, the monobasic acidester includes, for example, glycol-based esters obtained by reactingtriethylene glycol with organic acids such as butyric acid, isobutyricacid, caproic acid, 2-ethylbutyric acid, heptanoic acid, n-octylic acid,2-ethylhexylic acid, pelargonic acid (n-nonylic acid), and decylic acid;and esters of tetraethylene glycol or tripropylene glycol with the aboveorganic acids. The polybasic acid ester includes, for example, esters oforganic acids such as adipic acid, sebacic acid, and azelaic acid with alinear or branched alcohol having 4 to 8 carbon atoms.

Specific examples of the organic ester-based plasticizer includetriethylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethylhexoate, triethylene glycol dicapriate, triethylene glycol di-n-octoate,triethylene glycol di-n-heptoate, tetraethylene glycol di-n-heptoate,dibutyl sebacate, dioctyl azelate, dibutylcabitol adipate, ethyleneglycol di-2-ethyl butyrate, 1,3-propylene glycol di-2-ethyl butyrate,1,4-propylene glycol di-2-ethyl butyrate, 1,4-butylene glycol di-2-ethylbutyrate, 1,2-butylene glycol di-2-ethylene butyrate, diethylene glycoldi-2-ethyl butyrate, diethylene glycol di-2-ethyl hexoate, dipropyleneglycol di-2-ethyl butyrate, triethylene glycol di-2-ethyl pentoate,tetraethylene glycol di-2-ethyl butyrate, and diethylene glycoldicapriate.

Examples of the phosphoric acid-based plasticizer lo includetributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropylphosphite.

Among these plasticizers for interlayer film, at least one selected fromthe group consisting of dihexyl adipate (DHA), triethylene glycoldi-2-ethylhexanoate (3GO), tetraethylene glycol di-2-ethylhexanoate(4GO), triethylene glycol di-2-ethyl butyrate (3GH), tetraethyleneglycol di-2-ethyl butyrate (4GH), tetraethylene glycol di-heptanoate(4G7), and triethylene glycol di-heptanoate (3G7) is preferable becausethe addition of a metal salt of a carboxylic acid having 5 to 6 carbonatoms, as an adhesion adjustor, makes it possible to preventdeterioration of adhesion between the interlayer film and the glass andto reconcile prevention of whitening and prevention of deterioration ofadhesion over time. Among these plasticizers, triethylene glycoldi-2-ethylhexanoate (3GO), triethylene glycol di-2-ethyl butyrate (3GH),tetraethylene glycol di-2-ethylhexanoate (4GO), and dihexyl adipate(DHA) are particularly preferable because hydrolysis is less likely tooccur.

In the present invention, an organic solvent containing alcohols as amain component is used. The alcohols are not specifically limited. Forexample, at least one selected from the group consisting of methanol,ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol,tert-butanol, lauryl alcohol, diacetone alcohol, cyclohexanol, ethyleneglycol, diethylene glycol, and triethylene glycol is preferable. In thecase in which the organic solvent containing alcohols as a maincomponent (i.e., alcohol solvent) contains a small amount of componentsother than alcohols, methyl ethyl ketone, isopropyl acetate, ethyllactate, 2-pyrrolidone, and ethyl acetoacetate can be used as thecomponent.

Since the organic solvent containing alcohols as a main component isexcellent in affinity with ITO fine particles and is also excellent incompatibility with the plasticizer for an interlayer film, thereflection value measured by a goniophotometric measurement can bereduced to 30. or less, and preferably 25 or less. Here, the reflectionvalue measured by a goniophotometric measurement is a value obtained bysubtracting a reference value which is a measured value of a plasticizerfilled in a glass cell having an optical path length 1 mm with, from araw data of a dispersion of ITO fine particles measured at 0 degreesamong reflected light distribution at an incidence angle of 45 degrees.Furthermore, a reflection yellow index having a correlation with themeasured reflection value can be increased to −20 or more. Also, effectof preventing solvent shock is exerted. Furthermore, effect ofsuppressing a variation in a dispersion property caused by the kind ofthe plasticizer for an interlayer film is exerted.

The dispersion stabilizer is preferably a compound containing at leastone atom selected from the group consisting of nitrogen, phosphorus, andchalcogen atoms. These atoms are excellent in affinity with ITO fineparticles and good dispersion effect can be exerted. Examples of thecompound include (I) anionic surfactants such as carboxylic acid salt,sulfonic acid salt, sulfate ester salt, phosphate ester salt,polymerization type polymer, and polycondensation type polymer; (II)nonionic surfactants such as ether, ester, ester ether, andnitrogen-containing one; (III) cationic surfactants such as primaryamine salt or tertiary amine salt, quaternary ammonium salt andpolyethylenepolyamine derivative; and (IV) amphoteric surfactants suchas carboxybetaine, aminocarboxylic acid salt, sulfobetaine, aminosulfateester, and imidazoline. Among these compounds, at least one selectedfrom sulfate ester-based compound, phosphate ester-based compound,ricinoleic acid, polyricinoleic acid, polycarboxylic acid, polyhydricalcohol type surfactant, polyvinyl alcohol, and polyvinyl butyral isparticularly preferable.

Examples of the phosphate ester-based compound include polyoxyethylenealkyl ether phosphoric acid ester, alkyl ether phosphoric acid ester,and polyoxyethylene alkyl phenyl ether phosphoric acid ester.

The dispersion stabilizer is preferably at least one selected from thegroup consisting of chelate, inorganic acid, and organic acid. Thechelate is not specifically limited, and for example,ethylenediaminetetraacetic acids (EDTA) and β-diketones can be used.Among these chelates, β-diketones are preferable because of excellentcompatibility with the plasticizer for an interlayer film and the resin,and acetylacetone is particularly preferable. As the β-diketones, forexample, benzoyltrifluoroacetone and dipivaloylmethane may also be used.These chelates prevent agglomeration of ITO fine particles and reducethe reflection value measured by a goniophotometric measurement, andalso can enhance the reflection yellow index having a correlation withthe measured reflection value.

The inorganic acid is not specifically limited. For example,hydrochloric acid and nitric acid can be used. Also, the organic acid isnot specifically limited. For example, aliphatic carboxylic acid,aliphatic dicarboxylic acid, aromatic carboxylic acid, and aromaticdicarboxylic acid can be used. Specific examples thereof include benzoicacid, phthalic acid, and salicylic acid. Among these, a C2-C18 aliphaticcarboxylic acid is preferable and a C2-C10 aliphatic carboxylic acid ismore preferable. Examples of the C2-C10 aliphatic carboxylic acidinclude acetic acid, propionic acid, n-butyric acid, 2-ethylbutyricacid, n-hexanoic acid, 2-ethylhexanoic acid, and n-octanoic acid. Theseinorganic and organic acids prevent agglomeration of ITO fine particlesand reduce the reflection value measured by a goniophotometricmeasurement, also can enhance the reflection yellow index having acorrelation with the measured reflection value.

In the dispersion of ITO particles of the present invention, in order toexhibit initial optical performances by high dispersion of ITO fineparticles, a combination of the plasticizer for an interlayer film,which serves as a dispersion medium, and a dispersion stabilizer is veryimportant. For example, in the case of using triethylene glycoldi-2-ethylhexanoate (3GO) as the plasticizer for an interlayer film,when alcohols are used as the solvent and three components of the abovephosphate ester-based compound, the organic acid such as 2-ethylhexanoicacid, and the chelate such as acetylacetone are used in combination asthe dispersion stabilizer, ITO fine particles can be dispersed with highconcentration and high dispersibility and the reflection value measuredby a goniophotometric measurement can be reduced, and also thereflection yellow index having a correlation with the measuredreflection value can be enhanced. Furthermore, solvent shock can beprevented in the case of diluting with the plasticizer for an interlayerfilm. In this case, alcohols are preferably methanol, ethanol,isopropanol and diacetone alcohol.

There have been known compositions obtained by adding 3GO as theplasticizer to a solution containing ITO fine particles dispersed inpolyphosphate ester and acetylacetone and a composition obtained byfurther mixing the composition with 2-ethylhexanoic acid. However, thesecompositions have a drawback in that they are free of alcohols and havehigh hydrophobicity, and thus ITO fine particles are inferior inaffinity with the solution and solvent shock may arise. Also, thedispersion proprety drastically vary depending on the kind of theplasticizer for an interlayer film and it is hard to control thedispersion proprety.

The dispersion system, in which three components of the above phosphateester-based compound, the organic acid such as 2-ethylhexanoic acid, andthe chelate such as acetylacetone are used in combination, also hasexcellent effect of easily controlling the degree of adhesion at theinterface between the interlayer film and the glass. In the laminatedglass, in the case in which the degree of adhesion at the interfacebetween the interlayer film and the glass is too low, exfoliation occursat the interface between the glass and the interlayer film. On the otherhand, in the case in which the degree of adhesion is too high,penetration resistance of the laminated glass is lowered. Therefore, anadvantage of easily controlling the degree of adhesion at the interfacebetween the interlayer film and the glass is very useful. Also, there isan advantage that a variation in the degree of adhesion at the interfacebetween the glass and the interlayer film caused by a change in moistureof the interlayer film is easily suppressed.

The dispersion stabilizer, other than the chelate, the organic acid, andthe inorganic acid, functions as a surfactant for enhancing aninteraction between an organic interface and an inorganic interface, andtherefore enhances the degree of adhesion at the interface between theinterlayer film and the glass. As a result, it is hard to properlycontrol the degree of adhesion between the glass and the interlayer filmonly by an adhesion adjustor such as an alkali metal salt and/or analkali earth metal salt, and it is particularly hard to control thedegree of adhesion to be a low value. However, when the above threecomponents are used in combination, it is believed that these componentscordinate to the adhesion adjustor such as the alkali metal salt and/orthe alkali earth metal salt which is for controlling the degree ofadhesion at the interface between the interlayer film and the glass,thereby controllability of the adhesion adjustor is enhanced. As aresult, as described above, the degree of adhesion can be controlledeven under the conditions in which the degree of adhesion at theinterface between the glass and the interlayer film is increased by thedispersion stabilizer.

In the dispersion of ITO fine particles of the present invention, whenmeasured under the conditions in which the concentration of ITO fineparticles is 0.7% by weight, and a glass cell having an optical pathlength of 1 mm is used, a visible light transmittance is 80% or more, asolar radiation transmittance at a wavelength within a range from 300 to2100 nm is ¾ or less of the visible light transmittance, a haze value is1.0% or less, and a reflection yellow index is −20 or more.Alternatively, the reflection value measured by a goniophotometricmeasurement under the above measuring conditions is 30 or less.

Among these, each of the haze value, the reflection yellow index, andthe reflection value measured by a goniophotometric measurement reflectsthe dispersion state of ITO fine particles in the dispersion of ITO fineparticles. The relation between the visible light transmittance and thesolar radiation transmittance reflects heat shield properties of the ITOfine particles themselves. The visible light transmittance and the solarradiation transmittance can be measured by the method defined inJapanese Industrial Standard (JIS R 3106). The haze value can bemeasured by the method defined in Japanese Industrial Standard (JIS K7105).

In the dispersion of ITO fine particles of the present invention, in thecase in which the visible light transmittance is less than 80%, theresulting interlayer film, in its turn, the laminated glass may have lowvisible light transmittance. In the case in which the solar radiationtransmittance at a wavelength within a range from 300 to 2100 nm is morethan ¾ of the visible light transmittance, the resulting interlayerfilm, in its turn, the laminated glass may be inferior in heat shieldproperties.

In the dispersion of ITO fine particles of the present invention, thereflection yellow index is −20 or more. The reflection yellow index canbe calculated by the following equation defined in Japanese IndustrialStandard (JIS K 7103). In the equation, X, Y and Z denote tristimusvalues due to the measurement of reflection of test samples in standardilluminant C.

Reflection yellow index=100(1.28X-1.06Z)/Y As a result of secondaryagglomeration of ITO fine particles, scattering of visible light in ashort wavelength range occurs and clouding of the dispersion system isinduced under a light source. The reason is believed to be as follows:when the ITO fine particles causes secondary agglomeration, the particlesize increases, thereby causing scattering of visible light in a shortwavelength range. In proportion to a large number of agglomerates, thereflectance of visible light in a short wavelength range becomes higherand clouding increases. Here, it is believed that the reflectance (Z) ofvisible light in a short wavelength range of the dispersion of ITO fineparticles and the interlayer film containing ITO fine particles isproportional to clouding of the ITO fine particles in the dispersionsystem. That is, it is believed that the reflectance (Z) of visiblelight in a short wavelength range is proportional to the degree ofsecondary agglomeration of the ITO fine particles, and in the case inwhich the dispersibility is poor, the reflectance (Z) of visible lightin a short wavelength range becomes higher. In the case of the same ITOconcentration, absorption of visible light in a medium wavelength rangeis almost the same as that of visible light in a long wavelength range,and thus X and Y are almost the same. Therefore, in the case of the sameITO concentration, as the reflectance (Z) of visible light in a shortwavelength range becomes higher, the value of the reflection yellowindex decreases and clouding increases. Therefore, the use of thereflection yellow index (YI) as an indicator makes it possible to graspdispersibility of the ITO fine particles and to grasp transparency ofthe dispersion of ITO fine particles and the interlayer film containingITO fine particles. In the case of ITO fine particles having differentconcentrations, since the values of X and Y change and the level of thereflection yellow index increases, a relative comparison cannot be madesimply.

In the case in which the haze value of the dispersion of ITO fineparticles is more than 1.0% or the reflection yellow index is less than−20, the ITO fine particles are not sufficiently dispersed and theresulting interlayer film, in its turn, the laminated glass has poorhaze value and poor reflection yellow index. In the case in which thereflection value measured by a goniophotometric measurement is more than30, clouding occurs at a certain angle, resulting in poor transparency.

In the dispersion of ITO fine particles of the present invention, aslong as the visible light transmittance (Tv), the solar radiationtransmittance (Ts), the haze value, the reflection yellow index, and thereflectance as determined by a goniophotometer are within the aboverange, the concentration of the ITO fine particles is not specificallylimited. The dispersion may contain a plasticizer for an interlayerfilm, an organic solvent containing alcohols as a main component and adispersion stabilizer, and each content is not specifically limited.

The lower limit of the concentration of ITO fine particles is preferably0.1% by weight and the upper limit is preferably 95.0% by weight. In thecase in which the concentration of the ITO fine particles is not withinthe above range, it may become difficult to uniformly disperse the ITOfine particles. The lower limit of the concentration of ITO fineparticles is more preferably 10% by weight and the upper limit is morepreferably 60% by weight.

The content of the plasticizer for an interlayer film is preferably fromabout 1 to 99.9% by weight, the content of the organic solventcontaining alcohols as a main component is preferably from about 0.02 to25% by weight, and the content of the dispersion stabilizer ispreferably from about 0.0025 to 30% by weight. The concentration of theITO fine particles is more preferably from about 10 to 60% by weight,the content of the plasticizer for an interlayer film is more preferablyfrom about 10 to 85% by weight, the content of the organic solventcontaining alcohols as a main component is more preferably from about0.5 to 10% by weight, and the content of the dispersion stabilizer ismore preferably from about 0.02 to 20% by weight.

In the dispersion of ITO fine particles of the present invention, whenthe dispersion of ITO fine particles having an ITO fine particles of10.0 to 95.0% by weight is allowed to stand for a long period, ordiluted with the plasticizer for an interlayer film so as to adjust theconcentration of the ITO fine particles to 40.0% by weight, the meanvolume particle size of the ITO fine particles is preferably 80 nm orless and the particle size at 90% accumulation (D90) is preferably 160nm or less. In the case in which the mean volume particle size is morethan 80 nm or D90 is more than 160 nm, when mixing with the resin tomanufacture an interlayer film, the average particle of the ITO fineparticles in the interlayer film may increase, resulting in poortransparency. In the dispersion of ITO fine particles of the presentinvention, even when the concentration of the ITO fine particles isdecreased to 10.0% by weight by dilution, the mean volume particle sizeof the ITO fine particles is more preferably 80 nm or less and D90 ismore preferably 160 nm or less. Even if the dispersion of ITO fineparticles is partially or entirely solidified, fluidity is recovered byvigorous stirring or shaking, and the mean volume particle size becomes80 nm or less and the particle size at 90% accumulation (D90) becomes160 nm or less.

The method for manufacturing the dispersion of ITO fine particles of thepresent invention is not specifically limited, but is preferably amethod for mixing the organic solvent containing alcohol as a maincomponent (i.e. alcohol solvent), the dispersion stabilizer, the ITOfine particles, and the plasticizer for an interlayer film, anddispersing the ITO fine particles. The present invention includes thismethod for manufacturing the dispersion of ITO fine particles.

In the method for manufacturing the dispersion of ITO fine particles ofthe present invention, as a specific aspect of mixing the alcoholsolvent, the dispersion stabilizer, the ITO fine particles, and theplasticizer for an interlayer film, these components may besimultaneously mixed, or a mixed solution containing the alcoholsolvent, the dispersion stabilizer, and the tin-doped indium oxide fineparticles may be previously prepared and the mixed solution may be addedto the plasticizer for an interlayer film, thereby dispersing thetin-doped indium oxide fine particles in the plasticizer for aninterlayer film, or the tin-doped indium oxide fine particles may bedispersed in the plasticizer for an interlayer film by adding theplasticizer for an interlayer film to the mixed solution. As theplasticizer for an interlayer film, a plasticizer containing an alcoholsolvent and/or a dispersion stabilizer may be used. The compositionratio of the dispersion may be adjusted by evaporation until theconcentration of the organic solvent containing alcohols as a maincomponent reaches a predetermined concentration.

In the dispersion of ITO fine particles of the present invention, amixed solution containing a high concentration of ITO fine particlesdispersed therein may be previously prepared and the mixed solution maybe diluted with the plasticizer for an interlayer film, or a plasticizerfor an interlayer film containing the alcohol solvent and the dispersionstabilizer until the concentration of the ITO fine particles reach apredetermined concentration. In the dispersion of ITO fine particles ofthe present invention, such a dilution process makes it possible toobtain a dispersion of ITO fine particles free of solvent shock, whereinthe mean volume particle size of ITO fine particles is 80 nm or less,and the particle size at 90% accumulation (D90) is 160 nm or less, byappropriately selecting the plasticizer for an interlayer film, thealcohol solvent, and the dispersion stabilizer.

In the method for manufacturing the dispersion of ITO fine particles ofthe present invention, an apparatus used for mixing and dispersion isnot specifically limited. For example, extruder, plastograph, ball mill,beads mill, sand grinder, kneader, Banbury mixer, and calendering rollcan be used.

By using a resin composition obtained by mixing the dispersion of ITOfine particles of the present invention with the resin, an interlayerfilm for laminated glass with heat ray shield properties can bemanufactured. This laminated glass can have excellent opticalcharacteristics and excellent heat shield properties because the ITOfine particles are highly dispersed.

In the interlayer film, the ITO fine particles are preferably dispersedsuch that the average particle size is 80 nm or less. In the case inwhich the average particle size is more than 80 nm, severe scattering ofvisible light due to the ITO fine particles occurs and the resultinginterlayer film may be inferior in transparency. As a result, the hazevalue becomes worse when the laminated glass is assembled and thus itbecomes impossible to obtain high transparency required to a front glassof automobiles.

In the interlayer film, the ITO fine particles are preferably dispersedsuch that the number of particles having a particle size of 100 nm ormore is one per μm² or less. That is, the ITO fine particles arecommonly dispersed such that, when a heat ray shield interlayer film forlaminated glass is photographed and observed by a transmission electronmicroscope, ITO fine particles having a particle size of 100 μm or moreare not found or, if any, the number of ITO fine particles having aparticle size of 100 μm or more is only one per μm². When a laminatedglass is manufactured by using the interlayer film in such a dispersionstate, the resulting laminated glass has low haze value and is excellentin transparency and heat shield properties. The observation is conductedusing a transmission electron microscope (Model H-7100FA, manufacturedby Hitachi, Ltd.) at an acceleration voltage of 100 kV.

The resin to be mixed with the dispersion of ITO fine particles of thepresent invention is not specifically limited. For example, it may be aknown resin which is generally used as a transparent resin of theinterlayer film for laminated glass. Specific examples of the resininclude polyvinyl acetal resin, polyurethane resin, ethylene-vinylacetate resin, acrylic copolymer resin including, as a constituent unit,acrylic acid or methacrylic acid, or derivatives thereof, and vinylchloride-ethylene-glycidyl methacrylate copolymer resin. Among theseresins, polyvinyl acetal resin is preferable. These resins can be easilymanufactured by a known method or a method analogous to the knownmethod.

The polyvinyl acetal resin is not specifically limited as long as it isa polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol withaldehyde, and is particularly preferably polyvinyl butyral. Thepolyvinyl alcohol is usually obtained by saponifying vinyl polyacetate,and polyvinyl alcohol having a saponification degree of 80 to 99.8 mol %is generally used.

A molecular weight and a molecular weight distribution of the polyvinylacetal resin are not specifically limited. In view of formability andphysical properties, the lower limit of the polymerization degree of thepolyvinyl alcohol resin as a material is preferably 200 and the upperlimit is preferably 3000. In the case in which the polymerization degreeis less than 200, the resulting laminated glass may be inferior inpenetration resistance. On the other hand, in the case in which thepolymerization degree is more than 3000, the resin film is inferior informability and also the resin film has too high rigidity, resulting inpoor processability. The lower limit of the polymerization degree ismore preferably 500 and the upper limit is more preferably 2000.

Also, the aldehyde used for acetalization is not specifically limited.In general, aldehyde having 1 to 10 carbon atoms is used. Examplesthereof include n-butylaldehyde, isobutylaldehyde, n-valeraldehyde,2-ethylbutylaldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde,n-decylaldehyde, formaldehyde, acetaldehyde and benzaldehyde. Amongthese aldehydes, n-butylaldehyde, n-hexylaldehyde, and n-valeraldehydeare preferable, and butylaldehyde having 4 carbon atoms is particularlypreferable.

The polyvinyl acetal is preferably polyvinyl butyral acetalized bybutylaldehyde. Taking account of required physical properties, theseacetal resins may be appropriately blended in combination. Furthermore,a copolyvinyl acetal resin may be appropriately used in combination withaldehyde on acetalization. The lower limit of the acetalization degreeof the polyvinyl acetal resin used in the present invention ispreferably 40% and the upper limit is preferably 85%. The lower limit ismore preferably 60% and the upper limit is more preferably 75%.

When a polyvinyl acetal resin is used as the resin, the resincomposition preferably contains 20 to 60 parts by weight of aplasticizer for an interlayer film and 0.1 to 3 parts by weight of ITOfine-particles based on 100 parts by weight of the polyvinyl acetalresin. In the case in which the amount of the plasticizer for aninterlayer film is less than 20 parts by weight, penetration resistancemay be lowered. On the other hand, in the case in which the amount ismore than 60 parts by weight, bleed-out of the plasticizer occurs andtransparency or adhesion of the heat ray shield interlayer film forlaminated glass is lowered, and thus the resulting laminated glass mayhave large optical strain. The lower limit of the amount of theplasticizer for an interlayer film is more preferably 30 parts by weightand the upper limit is more preferably 60 parts by weight. In the casein which the amount of the ITO fine particles is less than 0.1 parts byweight, sufficient heat ray shield effect may not be exerted. On theother hand, in the case in which the amount is more than 3.0 parts byweight, visible light transmittance may be lowered and the haze valuemay increase.

Preferably, the resin composition further contains an adhesion adjustor.The adhesion adjustor is not specifically limited, and an alkali metalsalt and/or an alkali earth metal salt are preferably used. The alkalimetal salt and/or the alkali earth metal salt are not specificallylimited and examples thereof include salts of potassium, sodium, andmagnesium. The acid constituting the salts is not specifically limitedand examples thereof lo include organic acids, for example, carboxylicacids such as octylic acid, hexylic acid, butyric acid, acetic acid, andformic acid; and inorganic acids such as hydrochloric acid and nitricacid.

Among the above alkali metal salt and/or the alkali earth metal salt, analkali metal salt and an alkali earth metal salt of an organic acidhaving 2 to 16 carbon atoms are preferable, and a magnesium salt ofcarboxylic acid having 2 to 16 carbon atoms, and a potassium salt ofcarboxylic acid having 2 to 16 carbon atoms are preferable.

The magnesium or potassium salt of carboxylic acid having 2 to 16 carbonatoms is not specifically limited, and for example, magnesium acetate,potassium acetate, magnesium propionate, potassium propionate, magnesium2-ethylbutanoate, potassium 2-ethylbutanoate, magnesium 2-ethylhexanoateand potassium 2-ethylhexanoate are preferably used. These salts may beused alone or in combination.

The amount of the alkali metal salt and/or the alkali earth metal saltis not specifically limited. For example, when the resin is a polyvinylacetal resin, the lower limit of the amount is preferably 0.001 parts byweight based on 100 parts by weight of the polyvinyl acetal resin, andthe upper limit is preferably 1.0 parts by weight. In the case in whichthe amount is less than 0.001 parts by weight, the degree of adhesion inthe vicinity of the heat ray shield interlayer film for laminated glassmay be lowered under a high humidity atmosphere. In the case in whichthe amount is more than 1.0 parts by weight, the degree of adhesion maybe excessively lowered and transparency of the heat ray shieldinterlayer film for laminated glass may be lost. The lower limit of theamount is more preferably 0.01 parts by weight and the upper limit ismore preferably 0.2 parts by weight.

Preferably, the resin composition further contains an antioxidant. Theantioxidant is not specifically limited and examples of the phenolicantioxidant include 2,6-Di-tert-butyl-p-cresol (BHT) (“Sumilizer BHT”,manufactured by Sumitomo Chemical Industries Co., Ltd.) andtetrakis-[methylene-3-(3′-5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane(Irganox 1010, manufactured by Ciba Geigy Ltd.). These antioxidants maybe used alone or in combination. The amount of the antioxidant is notspecifically limited. For example, when the resin is a polyvinyl acetalresin, the lower limit of the amount is preferably 0.01 parts by weightbased on 100 parts by weight of the polyvinyl acetal resin, and theupper limit is preferably 5.0 parts by weight.

Preferably, the resin composition further contains an ultravioletabsorber. The ultraviolet absorber is not specifically limited andexamples thereof include benzotriazole-based compound,benzophenone-based compound, triazine-based compound, and benzoate-basedcompound.

The benzotriazole-based compound is not specifically limited andexamples thereof include 2-(2′-hydroxy-5′-methylphenyl)benzotriazole(Tinuvin P, manufactured by Ciba Geigy Ltd.),2-(2′-hydroxy-3′,5′-di-t-butylphenyl)benzotriazole (Tinuvin 320,manufactured by Ciba Geigy Ltd.),2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole (Tinuvin326, manufactured by Ciba Geigy Ltd.) and2-(2′-hydroxy-3′,5′-di-amylphenyl)benzotriazole (Tinuvin 328,manufactured by Ciba Geigy Ltd.).

The benzophenone-based compound is not specifically limited, andexamples thereof include octabenzone (Chimassorb 81, manufactured byCiba Geigy Ltd.). The triazine-based compound is not specificallylimited and examples thereof include2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (Tinuvin1577FF, manufactured by Ciba Geigy Ltd.). Furthermore, thebenzoate-based compound is not specifically limited and examples thereofinclude 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate(Tinuvin 120, manufactured by Ciba Geigy Ltd.).

The amount of the ultraviolet absorber is not specifically limited. Forexample, when the resin is a polyvinyl acetal resin, the lower limit ofthe amount is preferably 0.01 parts by weight based on 100 parts byweight of the polyvinyl acetal resin, and the upper limit is preferably5.0 parts by weight. In the case in which the lower limit is less than0.01 parts by weight, the effect of absorbing ultraviolet radiation maybe hardly exerted. In the case in which the upper limit is more than 5.0parts by weight, weatherability of the resin may be deteriorated. Thelower limit is more preferably 0.05 parts by weight and the upper limitis more preferably 1.0 parts by weight.

If necessary, the interlayer film for laminated glass including theresin composition may contain additives such as photostabilizers,surfactants, flame retardants, antistatic agents, moisture resistantagents, colorants, heat ray reflecting agents, and heat ray absorbers.Although the entire amount of the dispersion stabilizer contained in theresin composition may be derived from the dispersion of ITO fineparticles of the present invention, the dispersion stabilizer may beseparately added when the amount is insufficient. In this case, the samedispersion stabilizer as that described above can be used.

The method for manufacturing the interlayer film for laminated glass ofthe present invention is not specifically limited and includes, forexample, a method for mixing the ITO resin dispersion of the presentinvention with the above resin, and a plasticizer for an interlayer filmand/or additives, which are optionally added, such that the finalconcentration of the ITO fine particles is within an expected range toobtain a resin lo composition, and forming the mixture into a film usinga conventional film forming method such as extrusion method, calenderingmethod or pressing method. Among these methods, an extruding methodusing extruding machine in which two axes are arranged in parallel ispreferable and can further enhance the haze value. Using the resultinginterlayer film for laminated glass, a laminated glass having excellentheat ray shield properties can be manufactured. The method formanufacturing the laminated glass may be a conventionally known method.

The interlayer film for laminated glass of the present invention isconventionally used in the state of being interposed between laminatedglasses. As the glass, for example, high heat ray absorption glass,clear glass, and green glass are used. The high heat ray absorptionglass as used herein refers to a heat ray absorption glass wherein thevisible light transmittance is 75% or more and the transmittance is 65%or less in an entire wavelength range within a range from 900 to 1300nm.

The interlayer film and the laminated glass of the present invention hasheat ray shield properties, for example, under measuring conditions inwhich an interlayer film having a thickness of 0.76 mm is interposedbetween clear glass sheets having a thickness of 2.5 mm, theelectromagnetic wave shield properties at a frequency of 0.1 MHz to 26.5GHz are 10 dB or less, the haze value is 1.0% or less, the visible lighttransmittance is 70% or more, the solar radiation transmittance at awavelength within a range from 300 to 2100 nm is 80% or less of thevisible light transmittance, and the reflection yellow index is −12 ormore, which is preferably −10 or more, and more preferably −8 or more.

The electromagnetic wave shield properties act as an indicator whichrepresents the degree of attenuation when an electromagnetic wave at ameasured frequency penetrates through the interlayer film or thelaminated glass. In the case in which the electromagnetic wave shieldproperties are 10 dB or less, when using this laminated glass for thefront glass of automobiles, the latest mobile communication equipmentcan be used in the automobile without causing any problem.

The haze value of the interlayer film or the laminated glass of thepresent invention is 1.0% or less. In the case in which the haze valueis 1.0% or more, transparency of the interlayer film or the laminatedglass becomes insufficient for practical use.

In the interlayer film or the laminated glass of the present invention,the visible light transmittance is 70% or more. In the case in which thevisible light transmittance is less than 70%, transparency of theinterlayer film or the laminated glass becomes insufficient forpractical use. Therefore, it becomes impossible to pass the automotivefront glass regulation, and thus good visibility is adversely affected.

In the interlayer film or laminated glass of the present invention, thesolar radiation transmittance at a wavelength within a range from 300 to2100 nm is 80% or less of the visible light transmittance. In the casein which the visible light transmittance is more than 80%, transparencyof the interlayer film or the laminated glass becomes insufficient forpractical use.

In the interlayer film or laminated glass of the present invention, thereflection yellow index is −12 or more, preferably −10 or more, and motepreferably −8 or more. This means that scattering of visible light dueto ITO fine particles is less likely to occur, resulting in lessclouding. Here, when the concentration and the dispersion state are thesame, the reflection yellow index depends on the optical path length ofthe ITO fine particles dispersion, the dispersion medium, and quality ofthe glass. The reflection yellow index of the dispersion of ITO fineparticles is −20 or more under the measuring conditions due to the abovedispersion medium using a glass cell having an optical path length of 1mm. When the laminated glass was assembled, the optical path length isshorter than that described above and the medium contains the polyvinylacetal resin. Therefore, the reflection yellow index of the laminatedglass is preferably −12 or more.

In the interlayer film or laminated glass of the present invention, themeasured reflection value at 0 degrees among reflected lightdistribution at an incidence angle of 45 degrees measured by agoniophotometric measurement is 25 or less, preferably 20 or less, andmore preferably 15 or less. This means that scattering of visible lightdue to secondary agglomeration of ITO fine particles is less likely tooccur, resulting in less clouding. In the case in which the measuredreflection value is more than 25, clouding may occur and thetransparency of the resulting laminated glass becomes insufficient forpractical use. Here, the reflection value measured by a goniophotometricmeasurement is a value obtained by subtracting a measured reflectionvalue, as a reference, of a laminated glass obtained by interposing aninterlayer film containing no ITO fine particles dispersed thereinbetween two clear glass sheets, from a raw data of the interlayer filmor the laminated glass measured at 0 degrees among reflected lightdistribution at an incidence angle of 45 degrees.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in more detail by way ofexamples. The measurement and evaluation were conducted by the followingprocedures.

(A) Primary Average Particle Size of ITO Fine Particles

The primary average particle size was calculated from the measured valueof the specific surface area (BET) by the following equation. It hasbeen confirmed that the average particle size thus determined from thespecific surface area nearly agrees with the particle size determined bydirectly observing using a transmission electron microscope. Thespecific surface area due to a BET method was measured by using aBetasorb automatic surface area meter, Model 4200, manufactured byMicrotrac Inc.a (μm)=6/(ρ×B)(a: average particle size, ρ: true specific gravity, B: specific surfacearea (m²/g))(B) Crystal Lattice Constant of ITO Fine Particles

The lattice constant was determined by the following procedure. Using anautomatic X-ray diffractometer MO3X equipped with monochrometer,correction was conducted by a high-purity silicon single crystal(99.9999%) and spacing was calculated from a peak attributed to a planeindex (hkl), and then the lattice constant was determined by theleast-square method.

(C) Tv and Ts of Dispersion of ITO Fine Particles

Using a dispersion of ITO fine particles for evaluation (0.7% by weight)charged in a glass cell having an optical path length of 1 mm, thetransmittance at a wavelength within a range from 300 to 2100 nm wasmeasured by an autographic spectrophotometer (U-4000, manufactured byHitachi, Ltd.) and visible light transmittance (Tv) at a wavelengthwithin a range from 380 to 780 nm and a solar radiation transmittance(Ts) at a wavelength within a range from 300 to 2100 nm were determinedin accordance with Japanese Industrial Standard (JIS R 3106).

(D) Reflection Yellow Index of Dispersion of ITO Fine Particles

Using the same dispersion, measuring cell and autographicspectrophotometer as those used in (C), the reflectance at a wavelengthwithin a range from 380 to 780 nm was measured and the reflection yellowindex was calculated in accordance with Japanese Industrial Standard(JIS K 7103).

(E) Haze Value of Dispersion of ITO Fine Particles

Using the same dispersion and measuring cell as those used in (C), thehaze value was measured by a turbidimeter with integrating sphere(manufactured by Tokyo Denshoku Co., Ltd.) in accordance with JapaneseIndustrial Standard (JIS K 7105).

(F) Goniophotometric Measurement of ITO Fine Particles

Using the same dispersion and measuring cell as those used in (C),reflected light distribution-at an incidence angle of 45 degrees wasmeasured by an automatic goniophotometer (GP-200, manufactured byMurakami Color Research Laboratory) using a halogen lamp as the lightsource. Light is received at an angle within a range from −90 to 90degrees and a value was measured at 0 degrees among reflected lightdistribution. After measuring a laminated glass obtained by interposingan interlayer film containing no ITO fine particles dispersed thereinbetween two clear glass sheets, the value at 0 degrees was determinedand the resulting value was taken as a reference. The measurement of thedispersion was conducted in the same manner and the value obtained bysubtracting the reference from the measured value was taken as ameasured reflection value. The measurement was conducted under thefollowing conditions.

Light source intensity: 12V, 50W

Type of measurement: measurement of reflection

Light receiver: photomultiplier

Tilt angle of sample: 2.5 degrees

Conditions of light receiver:

-   -   SENSITIVITY ADJ: 999    -   HIGH VOLT ADJ: 999        (G) Particle Size of ITO Fine Particles in Dispersion of ITO        Fine Particles

Using a microtrac UPA particle size analyzer manufactured by NIKKISOCo., Ltd., particle size distribution of ITO fine particles in adispersion of ITO fine particles having a concentration of ITO fineparticles of 10% by weight was determined.

(H) Tv and Ts of Laminated Glass

Using an autographic spectrophotometer (U-4000, manufactured by Hitachi,Ltd.), the transmittance at a wavelength within a range from 300 to 2100nm of the laminated glass was measured and then the visible lighttransmittance (Tv) at a wavelength within a range from 380 to 780 nm andthe solar radiation transmittance (Ts) at a wavelength within a rangefrom 300 to 2100 nm were measured in accordance with Japanese IndustrialStandard (JIS R 3106 “Testing method on transmittance, reflectance, andemittance of flat glasses, and evaluation of solar heat gaincoefficient”).

(I) Reflection Yellow Index of Laminated Glass

Using an autographic spectrophotometer (U-4000, manufactured by Hitachi,Ltd.), the reflectance at a wavelength within a range from 380 to 780 nmwas measured and then the reflection yellow index was calculated inaccordance with Japanese Industrial Standard (JIS K 7103).

(J) Haze Value of Laminated Glass

Using a turbidimeter with integrating sphere (manufactured by TokyoDenshoku Co., Ltd.), the haze value of the laminated glass was measuredin accordance with Japanese Industrial Standard (JIS K7105).

(K) Electromagentic Wave Shield Properties (ΔdB) of Laminated Glass

In accordance with the KEC method (method for testing theelectromagnetic wave shield effect in a near field), the reflection loss(dB) for electromagnetic wave within the range of 0.1 to 10 MHz of thelaminated glass and that of a common float sheet glass with thethickness of 2.5 mm were measured respectively and were compared, andthe minimum and maximum differences between their reflection loss (dB)were described. With respect to the reflection loss (dB) forelectromagnetic wave within the range of 2 to 26.5 GHz, after standing a600 mm-square sample between a pair of transreceiver antennas, radiowaves from a radio signal generating apparatus were received by aspectrum analyzer and electromagentic wave shield properties of thesample were evaluated (method for testing the electromagnetic wave in aremote field).

(L) Goniophotometric Measurement of Interlayer Film and Laminated Glass

Using an automatic goniophotometer (GP-200, manufactured by MurakamiColor Research Laboratory) and using a halogen lamp as the light source,reflected light distribution at an incidence angle of 45 degrees wasdetermined. Light is received at an angle within a range from −90 to 90degrees and a value was measured at 0 degrees among reflected lightdistribution. After measuring a laminated glass obtained by interposingan interlayer film containing no ITO fine particles dispersed thereinbetween two clear glass sheets, the value at 0 degrees was determinedand the resulting value was taken as a reference. The measurement of thelaminated glass for evaluation was conducted and the value obtained bysubtracting the reference from the measured value was taken as ameasured reflection value. The measurement was conducted under thefollowing conditions.

Light source intensity: 12V, 50W

Type of measurement: measurement of reflection

Light receiver: photomultiplier

Tilt angle of sample: 2.5 degree

-   -   Conditions of light receiver:        -   SENSITIVITY ADJ: 999        -   HIGH VOLT ADJ: 999            (M) Dispersion State of ITO Fine Particles in Interlayer            Film

After preparing ultra-flake of the interlayer filmby using a microtome,the distribution of ITO fine particles were photographed and observedunder the following conditions by using a transmission electionmicroscope (TEM, Model H-7100FA, manufactured by Hitachi, Ltd.). Thephotographing was carried out in the range of 3 μm×4 μm at 20,000magnifications and enlarged at the time of printing. Obtained image wassubjected to a visual observation, particle sizes of all ITO fineparticles in the above observed scope are measured, and the averageparticle size was calculated as an mean volume particle size. Here, theparticle size of ITO fine particle was decided to be the longest one ofthe ITO fine particle. Also, counting the number of the fine particleshaving a particle size of 100 nm or more within the above-mentionedobserved scope, dividing them by 12 μm² of an observed space tocalculate the number of the particles per μm².

(N) Adhesion of Interlayer Film

The adhesion of the interlayer film to the glass was evaluated in termsof a pummel value. It is to be understood that the larger the pummelvalue, the higher the degree of adhesion to the glass, while the smallerthe pummel value, the lower the degree of adhesion to the glass. Thetest method is as follows. First, the laminate glass was allowed tostand at a temperature of −18±0.6° C. for 16 hours and then crushed witha hammer having a head weighing 0.45 kg until the glass fragments became6 mm or less in diameter. The degree of exposure of the film afterpartial exfoliation of glass was estimated by comparison with gradedlimit samples and the result was expressed in the pummel value accordingto the schedule shown below in Table 3. The degree of adhesion of theinterlayer film to the glass is preferably adjusted such that the pummelvalue is within a range from 3 to 6.

EXAMPLES Example 1

(Preparation of Dispersion of ITO Fine Particles)

10 Parts by weight ITO fine particles (primary average particle size: 20nm, crystal lattice constant: 10.12 Å), 1 part by weight of apolyoxyethylene alkyl ether phosphoric acid ester compound as thedispersant, 2 parts by weight of 2-ethylhexanoic acid, 3 parts by weightof acetylacetone, 4 parts by weight of ethanol as the organic solvent,and 80 parts by weight of triethylene glycol di-2-hexanoate (3GO) weremixed and dispersed to prepare a dispersion of ITO fine particles. Thiscomposition is shown in Table 1. This dispersion of ITO fine particleswas diluted with triethylene glycol di-2-hexanoate (3GO) so as to adjustthe concentration of the ITO fine particles to 0.7% by weight to obtaina dispersion of ITO fine particles for evaluation. The visible lighttransmittance (Tv), the solar radiation transmittance (Ts), the hazevalue, the reflection yellow index, the reflection value measured by agoniophotometric measurement of the dispersion having an ITOconcentration of 0.7% by weight are shown in Table 2. With respect tothe dispersion having an ITO-concentration of 10% by weight, the meanvolume particle size and particle size at 90% accumulation of the ITOfine particles are shown in Table 2 (Sample No. 1a).

34.5 Parts by weight of ITO fine particles, and a polyoxyethylene alkylether phosphoric acid ester compound, 2-ethylhexanoic acid,acetylacetone, ethanol, and 3GO, each of which amount is shown in Table1, were mixed to prepare a dispersion of ITO fine particles and then thedispersion of ITO fine particles was diluted with 3GO to obtain adispersion having an ITO concentration of 0.7% by weight and adispersion having an ITO concentration of 10% by weight. In the samemanner as in the case of the Sample No. 1a, physical properties of thesedispersions were determined. The results are shown in Table 2 (SampleNo. 1b).

Furthermore, 25 parts by weight of ITO fine particles, and apolyoxyethylene alkyl ether phosphoric acid ester compound,2-ethylhexanoic acid, acetylacetone, ethanol, and 3GO each of whichamount is shown in Table 1, were mixed to prepare a dispersion of ITOfine particles, and then the dispersion of ITO fine particles wasdiluted with 3GO to obtain a dispersion having an ITO concentration of0.7% by weight and a dispersion having an ITO concentration of 10% byweight. In the same manner as in the case of the Sample No. 1a, physicalproperties of these dispersions were determined. The results are shownin Table 2 (Sample No. 1c).

(Synthesis of Polyvinyl Butyral)

275 g of polyvinyl alcohol having an average polymerization degree of1700 and a saponification degree of 99.2 mol % was added to 2890 g ofpure water and then dissolved with heating. After the temperature of thesolution was controlled to 15° C., 201 g of hydrochloric acid having aconcentration of 35% by weight and 157 g of n-butylaldehyde were added,and then the mixed solution was maintained at 15° C., therebyprecipitating a reaction product. After the reaction was completed bymaintaining the reaction system at 60° C. for 3 hours, the reactionmixture was washed with an excess amount of water for washing awayunreacted n-butyraldehyde, neutralized with sodium hydroxide, which isthe common neutralizing agent, moreover washed with an excessive amountof water for 2 hours and dried to provide polyvinyl butyral resin as awhite powder with an average butyralization degree of 68.5 mol %.

(Production of Heat Ray Shield Interlayer Film for Laminated Glass)

To 100 parts by weight of a polyvinyl butyral resin, 2.8 parts by weightof a dispersion of ITO fine particles (ITO concentration: 10% by weight,Sample No. 1a) shown in Table 1 was added, and 3GO was added so as toadjust the ITO concentration to 0.2% by weight. Then magnesium2-ethylbutyrate and magnesium acetate were added appropriately to be 60ppm as magnesium content to the reaction mixture. The mixture wasmelt-kneaded thoroughly with a mixing roll and press-molded with apress-molding machine at 150° C. for 30 minutes to provide an interlayerfilm for laminated glass having an average thickness of 0.76 mm.

(Production of Laminated Glass)

The resulting interlayer film was interposed between two transparentfloat sheet glasses (30 cm×30 cm×2.5 mm thickness) and the assembly wasplaced in a rubber bag and deaerated under a vacuum of 2660 Pa for 20minutes. The deaerated assembly was transferred to an oven under suctionand pressed under vacuum at 90° C. for 30 minutes. The prebondedlaminated glass thus obtained was subjected to post-bonding in anautoclave at 135° C. and 118N/cm² for 20 minutes to provide a laminatedglass. Physical properties of the laminated glass were determined. Theresults are shown in Table 2 (Sample No. 1a).

An dispersion of ITO fine particles (ITO concentration: 34.5% by weight,Sample No. 1b) shown in Table 1 was mixed with polyvinyl butyral resinand then magnesium was added in the same amount as that in the case ofthe Sample No. 1a to prepare interlayer films (thickness: 0.76 mm)wherein the concentration of the ITO fine particles is 0.7% by weightand 0.2% by weight. Using the resulting interlayer films, a laminatedglass was manufactured in the same manner as in the case of the SampleNo. 1a. Physical properties of the laminated glass were determined. Theresults are shown in Table 2 (Sample No. 1b).

Example 2

In the same manner as in Example 1, except that ITO fine particleshaving a primary particle size and a lattice constant shown in Table 1were used and three kinds of dispersion stabilizers and alcohols wereused, and also the respective components were used in the amounts shownin Table 1, a dispersion of ITO fine particles was prepared. Thecomponents of this dispersion are shown in Table 1. An interlayer filmwas manufactured by diluting the dispersion with a plasticizer for aninterlayer film shown in Table 1 so as to adjust to the ITOconcentration to the value shown in Table 2, and then a laminated glasswas manufactured by using the interlayer film. Physical properties ofthe dispersion of ITO fine particles and the laminated glass weredetermined and evaluated. The results are shown in Table 2 (Samples No.2 to No. 9).

Example 3

In the same manner as in Example 1, except that a compound shown inTable 1 was used as the plasticizer for an interlayer film and therespective components were used in the amounts shown in Table 1, adispersion of ITO fine particles was prepared. The components of thisdispersion are shown in Table 1. An interlayer film was manufactured bydiluting the dispersion with a plasticizer for an interlayer film shownin Table 1 so as to adjust to the ITO concentration to the value shownin Table 2, and then a laminated glass was manufactured by using theinterlayer film. Physical properties of the dispersion of ITO fineparticles and the laminated glass were determined and evaluated. Theresults are shown in Table 2 (Samples No. 10 to No. 12).

Test Example

Using ITO fine particles, a plasticizer for an interlayer film, adispersion stabilizer and alcohols shown in Table 1 in the amount shownin Table 1, a dispersion of ITO fine particles was manufactured. Aninterlayer film was manufactured by diluting the dispersion with aplasticizer for an interlayer film shown in Table 1 so as to adjust tothe ITO concentration to the value shown in Table 2, and then alaminated glass was manufactured by using the interlayer film. Physicalproperties of the dispersion of ITO fine particles and the laminatedglass were determined and evaluated. The results are shown in Table 2(Samples No. 13 to No. 14).

Comparative Example

Using ITO fine particles having a slightly large lattice constant andusing a plasticizer for an interlayer film, a dispersion stabilizer, andalcohols shown in Table 1 in the amount shown in Table 1, a dispersionof ITO fine particles was manufactured. Using ITO fine particles, aplasticizer for an interlayer film, a dispersion stabilizer, andalcohols shown in Table 1 in the amount shown in Table 1, a dispersionof ITO fine particles was manufactured. A laminated glass wasmanufactured by using these dispersions. Physical properties of thedispersion of ITO fine particles and the laminated glass were determinedand evaluated. The results are shown in Table 2 (Samples No. 15 to No.18).

In the same manner as in Example 1, except that a dispersion stabilizerand alcohols were not used and only a plasticizer for an interlayer filmwas used, a dispersion of ITO fine particles was prepared. Thecomponents of this dispersion are shown in Table 1. A laminated glasswas manufactured using the dispersion. Physical properties of thedispersion of ITO fine particles and the laminated glass were determinedand evaluated. The results are shown in Table 2 (Sample No. 19).

In the same manner as in Example 1, except that alcohols were not usedand one kind of sulfate ester or n-butyric acid was used as thedispersion stabilizer, a dispersion of ITO fine particles was prepared.The components of this dispersion are shown in Table 1. A laminatedglass was manufactured using the dispersion. Physical properties of thedispersion of ITO fine particles and the laminated glass weredetermined. The results are shown in Table 2 (Samples No. 20 to No. 21).

In the same manner as in Example 1, except for using the components ofthe Samples No. 1a, No. 2, and No. 12 shown in Table 1, excludingalcohols, a dispersion of ITO fine particles was prepared. A laminatedglass was manufactured using the dispersion. Physical properties of thedispersion of ITO fine particles and the laminated glass weredetermined. The results are shown in Table 2 (Samples No. 22, No. 23,and No. 24).

In the same manner as in Example 1, except that a dispersion stabilizerwas not used and a plasticizer and alcohols were used, a dispersion ofITO fine particles was prepared. The components of this dispersion areshown in Table 1. A laminated glass was manufactured using thedispersion. Physical properties of the dispersion of ITO fine particlesand the laminated glass were determined. The results are shown in Table2 (Sample No. 25).

In the same manner as in Example 1, except that the same ITO fineparticles and plasticizer for an interlayer film as those in Example 1and also an anionic surfactant or a higher fatty acid ester was used asshown in Table 1, a dispersion of ITO fine particles was prepared. Thecomponents of this dispersion are shown in Table 1. A laminated glasswas manufactured using the dispersion. Physical properties of thedispersion of ITO fine particles and the laminated glass weredetermined. The results are shown in Table 2 (Samples No. 26 to No. 27).

As shown in Table 1 and Table 2, the dispersion of ITO fine particlesand laminated glasses of Examples (No. 1 to No. 12) of the presentinvention show high visible light transmittance (Tv), low haze value,and high absolute value of the reflection yellow index as compared withComparative Samples (No. 16 to No. 21, No. 25 to No. 27). The laminatedglasses of Examples (No. 1 to No. 12) of the present invention showextremely low value measured by a goniophotometric measurement,extremely low mean volume particle size, and extremely low number ofparticles having a particle size larger than 100 nm as compared with theComparative Samples (No. 16 to No. 21, No. 25 to No. 27). In allsamples, the pummel value was 4 and was controlled within a preferablerange.

The Sample No. 13 containing no n-butyric acid as the dispersionstabilizer and the Sample No. 14 containing no acetylacetone as thedispersion stabilizer are excellent in visible light transmittance,solar radiation transmittance, haze value, reflection yellow index,reflection value measured by a goniophotometric measurement, and pummelvalue.

In the case of the Comparative Sample No. 15 wherein ITO fine particleshave a slightly large lattice constant, a ratio of the solar radiationtransmittance to the visible light transmittance is not within the rangeof the present invention. In the case of the Comparative Samples (No. 16to No. 21, No. 25 to No. 27), the haze value of the dispersion of ITOfine particles is more than 1.0% and the reflection yellow index isconsiderably less than −20 and also the reflection value measured by agoniophotometric measurement is more than 40. The haze value of theinterlayer film for laminated glass is more than 1.0% and the reflectionyellow index is within a range from −15 to −18 and also the reflectionvalue measured by a goniophotometric measurement is within a range from29 to 66, and thus all of them are not within the range of the presentinvention.

In the case of the Comparative Samples No. 22 to No. 24, the haze valueof the dispersion of ITO fine particles is more than 1.0% and thereflection yellow index is less than −20 and also the reflection valuemeasured by a goniophotometric measurement is more than 50. In the caseof the Samples No. 22 and No. 23, the haze value of the interlayer filmfor laminated glass is 1.0% or less, while the haze value is more than1.0% in the case of the Sample No. 24. The reflection yellow index iswithin a range from −14 to −18 and the reflection value measured by agoniophotometric measurement is within a range from 38 to 66, and thusnone of them are within the range of the present invention. TABLE 1 ITOfine particles Primary Lattice Plasticizer for interlayer Dispersionstabilizer 1 No. particle size constant Amount Kind Amount Kind Amount 1a 20 10.12 10 3GO 80 Phosphate ester 1  1b 20 10.12 34.5 3GO 31Phosphate ester 3.4  1c 20 10.12 25 3GO 50 Phosphate ester 2.5  2 2510.14 30 3GO 55 Phosphate ester 5  3 80 10.15 50 3GO 30 Phosphate ester6  4 70 10.14 60 3GO 10 Phosphate ester 4  5 30 10.11 20 3GO 75 Sulfateester 0.01  6 45 10.14 40 3GO 45 Sulfate ester 2  7 60 10.16 10 3GO 85Sulfate ester 0.5  8 40 10.14 30 3GO 55 Polyvinyl alcohol 2  9 50 10.1550 3GO 24 Polyvinyl alcohol 7 10 20 10.12 10 3GH 80 Phosphate ester 1 1120 10.12 10 4GO 80 Phosphate ester 1 12 20 10.12 10 DHA 80 Phosphateester 1 13 20 10.12 10 3GO 79 Sulfate ester 2 14 20 10.12 10 3GO 79Sulfate ester 2 15 20 10.18 10 3GO 76 Sulfate ester 2 16 210 10.16 103GO 76 Sulfate ester 2 17 20 10.12 10 3GO 78 — — 18 20 10.12 10 3GO 81 —— 19 20 10.12 10 3GO 90 — — 20 20 10.12 10 3GO 88 Sulfate ester 2 21 2010.12 10 3GO 87 — — 22 20 10.12 10 3GO 84 Phosphate ester 1 23 25 10.1430 3GO 62 Phosphate ester 5 24 20 10.12 10 DHA 84 Phosphate ester 1 2520 10.12 10 3GO 84 — — 26 20 10.12 10 3GO 88 Higher fatty acid ester: 2%by weight 27 20 10.12 ITO fine particles: 30 parts by weight,Di-2-ethylhexyl phthalate: 70 parts by weight, Anionic surfactant: 3parts by weight Dispersion stabilizer 2 Dispersion stabilizer 3 AlcoholsNo. Kind Amount Kind Amount Kind Amount  1a 2-ethylhexanoic acid 2Acetylacetone 3 Ethanol 4  1b 2-ethylhexanoic acid 7 Acetylacetone 10.3Ethanol 13.8  1c 2-ethylhexanoic acid 5 Acetylacetone 7.5 Ethanol 10  22-ethylbutyric acid 2 Acetylacetone 1 Methanol 7  3 n-hexanoic acid 3Acetylacetone 6 Isopropanol 5  4 n-butyric acid 8Benzoyltrifluoroacetone 8 Diacetone alcohol 10  5 n-hexanoic acid 0.005Acetylacetone 0.005 Ethanol 4.98  6 2-ethylhexanoic acid 5Benzoyltrifluoroacetone 2 Isopropanol 6  7 2-ethylbutyric acid 1Benzoyltrifluoroacetone 3 Diacetone alcohol 0.5  8 n-butyric acid 3Benzoyltrifluoroacetone 5 Methanol 5  9 n-hexanoic acid 4Benzoyltrifluoroacetone 7 Diacetone alcohol 8 10 2-ethylhexanoic acid 2Acetylacetone 3 Ethanol 4 11 2-ethylhexanoic acid 2 Acetylacetone 3Ethanol 4 12 2-ethylhexanoic acid 2 Acetylacetone 3 Ethanol 4 13 —Acetylacetone 3 Isopropanol 6 14 n-butyric acid 3 — — Isopropanol 6 15n-butyric acid 3 Acetylacetone 3 Isopropanol 6 16 n-butyric acid 3Acetylacetone 3 Isopropanol 6 17 n-butyric acid 3 Acetylacetone 3Isopropanol 6 18 — — Acetylacetone 3 Isopropanol 6 19 — — — — — — 20 — —— — — — 21 n-butyric acid 3 — — — — 22 2-ethylhexanoic acid 2Acetylacetone 3 — — 23 2-ethylbutyric acid 2 Acetylacetone 1 — — 242-ethylhexanoic acid 2 Acetylacetone 3 — — 25 — — — — Isopropanol 6 26Higher fatty acid ester: 2% by weight — — 27 ITO fine particles: 30parts by weight, — — Di-2-ethylhexyl phthalate: 70 parts by weight,Anionic surfactant: 3 parts by weight(Note)The primary particle size is a primary average particle size (nm), thelattice constant is Å, the fatty acid ester is polyglycerin fatty acidester, and the unit of the amount is % by weight.

TABLE 2 dispersion of ITO fine particles 0.7 wt % solution 10 wt %solution Reflection Volume Tv Ts Haze Reflection measured particle No. %% % YI value size nm D90 nm  1a 91.9 64.5 0.4 −8.1 4.6 43 75  1b 91.964.5 0.4 −8.1 4.7 43 75  1c 91.9 64.5 0.4 −8.1 5.0 43 75  2 91.7 64.50.5 −8.7 4.7 44 76  3 89.2 60.3 0.8 −18.3 9.3 75 152  4 91.8 66.6 0.6−11 5.3 42 74  5 91.5 64.1 0.5 −7.5 5.3 39 78  6 91.7 66.6 0.5 −11.3 4.838 73  7 91.6 66.4 0.6 −11.3 5.3 50 77  8 91.0 64.3 0.5 −9.8 4.9 42 80 9 90.2 65.6 0.6 −15.3 4.7 60 130 10 91.8 64.5 0.4 −8.5 4.8 45 78 1191.9 64.5 0.4 −8.1 5.1 44 78 12 91.5 64.0 0.5 −8.9 4.8 48 80 13 91.865.5 0.5 −11.5 4.9 50 80 14 91.9 66.1 0.5 −11.9 5.2 52 85 15 91.9 69.20.4 −7.9 4.9 41 74 16 80.1 49.8 1.5 −30.8 68.9 180 280 17 82.0 54.0 2.1−26.0 40.5 100 205 18 81.6 53.7 2.1 −26.0 72.4 100 200 19 80.2 50.6 3.2−32.6 82.2 140 300 20 89.0 60.5 1.2 −24.0 53.4 85 170 21 81.1 52.8 2.8−30.5 73.5 130 290 22 91.2 63.8 1.2 −22.5 50.2 85 170 23 90.9 63.5 1.3−23.0 52.5 85 170 24 82.3 53.5 2.5 −30.0 72.8 120 270 25 81.8 53.8 2.2−26.5 49.4 100 210 26 84.3 57.8 1.2 −23.5 39.7 83 165 27 84.0 57.4 1.2−23.8 42.6 90 170 Interlayer film for laminated glass Number ofparticles having a ITO Eelectromagentic Reflection Volume particle sizeconcen- Tv Ts Haze transmission Reflection measured particle of 100 nmPummel No. tration % % % properties YI value size nm or more value  1a0.2 87.2 67.6 0.4 3 −4.0 1.1 55 0 4  1b 0.7 83.2 56.5 0.6 3 −7.3 3.6 700 4 0.2 87.2 67.6 0.4 3 −3.9 1.2 50 0 4  1c 0.7 83.2 56.9 0.6 3 −7.5 3.770 0 4  2 0.2 87.9 67.6 0.4 3 −4.2 1.2 60 0 4  3 0.2 86.6 62.2 0.8 3−7.9 2.1 78 1 4  4 0.7 83.5 58 0.7 3 −7.5 3.8 70 1 4  5 0.7 83.5 56.50.6 3 −5.7 3.6 58 0 4  6 0.2 87.4 67.5 0.4 3 −4.9 1.3 55 0 4  7 0.7 83.257.6 0.6 3 −7.4 4.2 65 0 4  8 0.2 87.0 65.9 0.5 3 −6.0 1.3 65 0 4  9 0.783.5 58 0.8 3 −7.5 3.6 70 1 4 10 0.2 87.3 66.6 0.4 3 −4.1 1.2 50 0 4 110.2 87.3 66.6 0.4 3 −3.9 1.2 50 0 4 12 0.2 87.0 65.7 0.5 3 −4.5 1.3 55 04 13 0.2 87.1 68.2 0.5 3 −5.5 1.3 60 0 6 14 0.2 87.0 68.1 0.5 3 −5.6 1.360 0 6 15 0.2 87.3 70.5 0.4 3 −3.6 1.3 48 0 4 16 0.2 76.0 48.8 1.5 3−17.2 53.6 210 7 4 17 0.2 78.5 53.0 1.4 3 −17.1 39.6 105 3 3 18 0.2 78.152.5 1.4 3 −17.0 62.5 105 3 3 19 0.2 76.4 49.5 1.7 3 −18.1 65.6 125 4 320 0.2 86.2 62.2 1.2 3 −15.8 39.5 90 2 8 21 0.2 77.0 51.2 1.5 3 −17.659.6 120 4 3 22 0.2 86.4 67.0 0.7 3 −14.5 38.0 90 2 4 23 0.2 87.1 67.20.8 3 −15.1 39.0 90 2 4 24 0.2 78.2 52.2 1.8 3 −18.5 66.2 130 4 4 25 0.278.2 52.7 1.4 3 −17.1 50.0 110 3 3 26 0.2 80.5 51.8 1.2 3 −15.4 29.5 902 8 27 0.2 80.0 51.2 1.2 3 −15.6 31.1 90 2 8(Note)The reflection YI is a reflection yellow index, the reflection value isa value measured by a goniophotometric measurement, the volume particlesize is a mean volume particle size, the electromagnetic shieldproperties are (ΔdB), and the number of particles having a particle sizeof 100 nm or more is (number/μm²).

TABLE 3 Exposure degree of interlayer film (%) 100 90 85 60 40 20 10 5 2or less Pummel value 0 1 2 3 4 5 6 7 8

INDUSTRIAL APPLICABILITY

The dispersion of tin-doped indium oxide fine particles of the presentinvention is excellent in dispersibility of tin-doped indium oxide fineparticles and has high transparency at a certain angle, and is also lesslikely to cause solvent shock and maintains good dispersion state oftin-doped indium oxide fine particles when the dispersion is mixed withthe resin. This dispersion of tin-doped indium oxide fine particles issuited for the manufacture of an interlayer film for laminated glass,and an interlayer film for laminated glass with excellent heat rayshield properties and a laminated glass including the same can beobtained by using the dispersion.

1. A dispersion of tin-doped indium oxide fine particles, the dispersioncomprising tin-doped indium oxide fine particles, a plasticizer for aninterlayer film, an organic solvent containing alcohols as a maincomponent, and a dispersion stabilizer, wherein under measuringconditions of a concentration of the tin-doped indium oxide fineparticles of 0.7% by weight and an optical path length of a glass cellof 1 mm, a visible light transmittance is 80% or more, a solar radiationtransmittance at a wavelength within a range from 300 nm to 2100 nm is ¾or less of the visible light transmittance, a haze value is 1.0% orless, and a reflection yellow index is −20 or more.
 2. The dispersion oftin-doped indium oxide fine particles according to claim 1, whereininstead of the reflection yellow index being −20 or more, or with thereflection yellow index being −20 or more, under measuring conditions ofthe optical path length of the glass cell of 1 mm, a reflection value at0 degrees among reflected light distribution at an incidence angle of 45degrees measured by a goniophotometer is 30 or less.
 3. The dispersionof tin-doped indium oxide fine particles according to claim 1, whereinthe plasticizer for an interlayer film is at least one selected from thegroup consisting of dihexyl adipate, triethylene glycoldi-2-ethylhexanoate, tetraethylene glycol di-2-ethylhexanoate,triethylene glycol di-2-ethyl butyrate, tetraethylene glycol di-2-ethylbutyrate, tetraethylene glycol di-heptanoate, and triethylene glycoldi-heptanoate.
 4. The dispersion of tin-doped indium oxide fineparticles according to claim 1, wherein the alcohols comprise at leastone selected from the group consisting of methanol, ethanol, propanol,isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, laurylalcohol, diacetone alcohol, cyclohexanol, ethylene glycol, diethyleneglycol, and triethylene glycol.
 5. The dispersion of tin-doped indiumoxide fine particles according to claim 1, wherein the dispersionstabilizer is a compound having at least one selected from the groupconsisting of nitrogen, phosphorus, and chalcogen atoms.
 6. Thedispersion of tin-doped indium oxide fine particles according to claim5, wherein the dispersion stabilizer is at least one selected from thegroup consisting of sulfate ester-based compound, phosphate ester-basedcompound, ricinoleic acid, polyricinoleic acid, polycarboxylic acid,polyhydric alcohol type surfactant, polyvinyl alcohol, and polyvinylbutyral.
 7. The dispersion of tin-doped indium oxide fine particlesaccording to claim 1, wherein the dispersion stabilizer is at least oneselected from the group consisting of chelate, inorganic acid, andorganic acid.
 8. The dispersion of tin-doped indium oxide fine particlesaccording to claim 1, wherein the dispersion of tin-doped indium oxidefine particles contains, as the dispersion stabilizer, three componentsof phosphate ester-based compound, organic acid, and chelate.
 9. Thedispersion of tin-doped indium oxide fine particles according to claim1, wherein a concentration of the tin-doped indium oxide fine particlesis from 0.1 to 95% by weight, a content of the plasticizer for aninterlayer film is from 1 to 99.9% by weight, a content of the organicsolvent containing alcohols as a main component is from 0.02 to 25% byweight, and a content of the dispersion stabilizer is from 0.0025 to 30%by weight.
 10. The dispersion of tin-doped indium oxide fine particlesaccording to claim 1, wherein the dispersion of tin-doped indium oxidefine particles is obtained by diluting a dispersion of tin-doped indiumoxide fine particles which contains tin-doped indium oxide fineparticles, a plasticizer for an interlayer film, an organic solventcontaining alcohols as a main component, and a dispersion stabilizer,and in which a concentration of the tin-doped indium oxide fineparticles is from 0.1 to 95% by weight, with a plasticizer for aninterlayer film, or a plasticizer for an interlayer film containing anorganic solvent containing alcohols as a main component and/or adispersion stabilizer.
 11. The dispersion of tin-doped indium oxide fineparticles according to claim 1, wherein, when a concentration of thetin-doped indium oxide fine particles is adjusted to 10.0% by weight bydiluting a dispersion of tin-doped indium oxide fine particles havingthe concentration of the tin-doped indium oxide fine particles of 10.0%by weight or more, or when a concentration of the tin-doped indium oxidefine particles is adjusted to 40.0% by weight by diluting a dispersionof tin-doped indium oxide fine particles having the concentration of thetin-doped indium oxide fine particles of 40.0% by weight or more, a meanvolume particle size of the tin-doped indium oxide fine particles is 80nm or less, and a particle size at 90% accumulation (D90) is 160 nm orless.
 12. The dispersion of tin-doped indium oxide fine particlesaccording to claim 1, wherein a primary average particle size of thetin-doped indium oxide fine particles is 0.2 μm or less.
 13. Thedispersion of tin-doped indium oxide fine particles according to claim1, wherein a lattice constant of a tin-doped indium oxide fine particlecrystal is from 10.11 to 10.16 Å.
 14. A method for manufacturing thedispersion of tin-doped indium oxide fine particles according to claim1, the method comprising mixing an organic solvent containing alcoholsas a main component, a dispersion stabilizer, tin-doped indium oxidefine particles, and plasticizer for an interlayer film, therebydispersing the tin-doped indium oxide fine particles.
 15. The method formanufacturing a dispersion of tin-doped indium oxide fine particlesaccording to claim 14, wherein a mixed solution containing the organicsolvent containing the alcohols as a main component, the dispersionstabilizer, and the tin-doped indium oxide fine particles is prepared,and this mixed solution is mixed with the plasticizer for an interlayerfilm to obtain a dispersion of tin-doped indium oxide fine particles.16. The method for manufacturing a dispersion of tin-doped indium oxidefine particles according to claim 15, wherein the mixed solutioncontaining the organic solvent containing the alcohols as a maincomponent, the dispersion stabilizer, and the tin-doped indium oxidefine particles is prepared, and this mixed solution is added to theplasticizer for an interlayer film, or the plasticizer for an interlayerfilm is added to this mixed solution, thereby dispersing the tin-dopedindium oxide fine particles.
 17. The method for manufacturing adispersion of tin-doped indium oxide fine particles according to claim15, wherein a plasticizer containing an organic solvent containingalcohols as a main component or a dispersion stabilizer is used as theplasticizer for an interlayer film.
 18. An interlayer film for heatshield laminated glass, which is formed by using a resin composition ofa mixture of the dispersion of tin-doped indium oxide fine particles ofclaim 1 and a resin, wherein, under measuring conditions in which theinterlayer film having a thickness of 0.76 mm is interposed betweenclear glass sheets having a thickness of 2.5 mm, electromagnetic waveshield properties at a frequency of 0.1 MHz to 26.5 GHz is 10 dB orless, a haze value is 1.0% or less, a visible light transmittance is 70%or more, a solar radiation transmittance at a wavelength within a rangefrom 300 to 2100 nm is 80% or less of the visible light transmittance,and a reflection yellow index is −12 or more.
 19. The interlayer filmfor laminated glass according to claim 18, wherein instead of thereflection yellow index being −12 or more or with the reflection yellowindex being −12 or more, a reflection value at 0 degrees among reflectedlight distribution at an incidence angle of 45 degrees measured by agoniophotometric measurement is 25 or less.
 20. The interlayer film forlaminated glass according to claim 18, wherein 20 to 60 parts by weightof the plasticizer for an interlayer film and 0.1 to 3 parts by weightof the tin-doped indium oxide fine particles based on 100 parts byweight of a polyvinyl acetal resin are contained.
 21. The interlayerfilm for laminated glass according to claim 20, wherein the polyvinylacetal resin is a polyvinyl butyral resin.
 22. The interlayer film forlaminated glass according to claim 18, wherein the resin compositionobtained by mixing the dispersion of tin-doped indium oxide fineparticles with the resin further contains an alkali metal salt and/or analkali earth metal salt as an adhesion adjustor.
 23. The interlayer filmfor laminated glass according to claim 18, wherein the tin-doped indiumoxide fine particles have an average particle size of 80 nm or less andare dispersed such that a number of particles having a particle size of100 nm or more is one per μm² or less.
 24. A laminated glass comprisingthe interlayer film for laminated glass of claim
 18. 25. The laminatedglass according to claim 24, wherein the laminated glass has heat rayshield properties in which electromagnetic wave shield performance at afrequency of 0.1 MHz to 26.5 GHz is 10 dB or less, a haze value is 1.0%or less, a visible light transmittance is 70% or more, a solar radiationtransmittance at a wavelength within a range from 300 to 2100 nm is 80%or less of the visible light transmittance, and a reflection yellowindex is −12 or more.
 26. The laminated glass according to claim 25,wherein instead of the reflection yellow index being −12 or more, orwith the reflection yellow index being −12 or more, a reflection valuemeasured at 0 degrees among reflected light distribution at an incidenceangle of 45 degrees measured by a goniophotometric measurement is 25 orless.